The shifting movements performed at the gearshift lever of the shifting device may be electronically transmitted to the transmission.
Shifting devices whose gearshift lever passes through a cover, at which the shift positions are optically displayed, have been known. The existing shift position symbols are usually illuminated permanently, and the corresponding symbol is illuminated more strongly in order to show to the driver of the vehicle which gear has been selected.
Such a shift position display is disclosed in, e.g., DE 296 06 501.3. Fatigue phenomena occur in the cables moved along with the gearshift lever, and the illumination of the shift position symbols is not perfectly homogeneous.
Shifting devices which transmit a signal corresponding to the shift position of the gearshift lever to a control unit of the transmission via sensors have been known, e.g., from DE 196 08 981.6. The function of detecting the signal, of coding, of processing and of transmitting are carried out at different points of the shifting, and the signals are transmitted via cables, plugs and additional elements. This design is error-prone and cost-intensive because of the many interfaces.
Printed circuit boards which can be assigned to one of two groups are currently known in the state of the art. Distinction is made between flexible printed circuit boards and rigid printed circuit boards.
Flexible printed circuit boards are difficult to handle because of the flexibility of the material of the printed circuit board during the insertion of components and mounting, and their dimensional stability is insufficient in the particular case. They are very expensive and are therefore unacceptable in the automobile industry because of the large numbers needed.
Rigid printed circuit boards are less expensive than flexible printed circuit boards and can be processed in a simpler manner.
They have a flat surface shape and can be provided with conductor strips on the top side and the underside. The components are inserted on these printed circuit boards in the flat state, soldered, and cooled after soldering.
So-called SMD (surface mounted devices) components have already proved successful for insertion on the printed circuit boards. These are components that are placed on the surface.
They require no holes in the printed circuit board any more to position and insert them, but they are placed on the solder paste applied to the printed circuit board beforehand by screen printing and are held in the position into which they are brought by an automatic inserting unit by the adhesive forces of the solder paste until the final soldering.
Printed circuit boards may be through hole plated, i.e., they may have conductor strips on both sides of the printed circuit board, wherein the said conductor strips are connected to one another at desired points by the conductor strips having through holes, which pass through the corresponding conductor strips to be connected and the printed circuit board, wherein this hole is lined with conductive material in order to establish the conductive connections between the perforated conductor strips to be connected. These rigid, flat printed circuit boards are installed in the flat state.
It is disadvantageous that a rigid printed circuit board cannot be bent later, i.e., after the components have already been inserted and it has been soldered, in order to adapt it, e.g., to a desired mounting situation, which would require a curved printed circuit board.
Even though a rigid printed circuit board is flexible to some extent, this flexibility is not sufficient to impart a permanent curvature to the printed circuit board; stresses, which would be transmitted to the conductor strips and to the terminals of the components, are generated in the material during the subsequent bending of the printed circuit board after soldering and the complete insertion of the components. A printed circuit board thus bent would display stresses in its material and could not withstand the loads occurring in the vehicle due to the prevailing operating conditions, such as vibrations, variations in temperature, etc.; the stress load of the components would unavoidably lead to preprogrammed failure of the printed circuit boards, the components or both together.
For example, small glow lamps, light-emitting diodes, etc., which are installed on flat printed circuit boards and are used to illuminate the shift position symbols, may be located under the cover of shifting devices, which usually have a bent or curved surface contour in order to optically better harmonize with the pivoting movement of the gearshift lever. However, problems linked with the gaping of the contour of the cover of the shifting device and the contour of the installed printed circuit board keep occurring in this case; e.g., the distance between the illuminating means and the symbols to be illuminated is not equal, which may lead to an undesired difference in the intensity of the illumination.